coding standard (GNU)

I feel I am quite like the coding standard with GNU by reading GTick.

1. variables and variable types are small characters. (add "_t" for types)

dsp_t* dsp;

2. function names are small characters, and written in this way: (in function name: words are connected by "_", this is my favorite way)

dsp_t* dsp_new(comm_t* comm);

3. comments in this layout.

 /* headers*/
#include < stdio.h>
#include < stdlib.h>

/*
 * brief.
 *
 * input:  from: data source of input
 *         from_size: the number of frames in [from]
 * output: to: the pointer to the allocated data.
 *
 * NOTE: here is the note. [to] should be free by the caller.
 */
static int foo(short* from, int from_size, unsigned char** to);

4. CONSTANTS and MACROES are large characters.

no writing permission on /tmp

I found myself has no writing permission on /tmp with FC5. It caused many troubles, firefox would not launch, because it creates temporary files when it starts... To solve it is quite simple:

$ cd /
$ sudo chmod 777 tmp

remove files in different directories

I used to know how to find files in different directories,
find . -name '*.raw' will list all the raw files, but how to delete them?

Here is the result:

[root@QSLENG13_FC5 xxx]# find . -name '*.raw' -exec ls {} \;
./SP-MIDI/output_midi.raw
./SMAF_MA-5/output_midi.raw
./SMAF_MA-3/output_midi.raw
./SMAF_MA-2/output_midi.raw
./MXMF/output_midi.raw
./MIDI_RIFF_Format_1/output_midi.raw
./MIDI_RIFF_Format_0/output_midi.raw
./MIDI_Format_1/output_midi.raw
./MIDI_Format_0/output_midi.raw
./KAR/output_midi.raw
./JTS/output_midi.raw
./iMelody/output_midi.raw
[root@QSLENG13_FC5 xxx]# find . -name '*.raw' -exec rm {} \;
[root@QSLENG13_FC5 xxx]# find . -name '*.raw' -exec ls {} \;

Another usage: I want remove GNU assembly code which is generated by ADS and all the other object files.

# find . \( -name '*.o.s' -o -name '*.o' \) -exec rm {} \;

or using "-ok" with control by the user (type 'y' or 'n' for each file).

[root@QSLENG13_FC5 linux]# find . \( -name '*.a' -o -name '*.so' \) -ok rm {} \;
< rm ... ./libmqcore32.a > ? n
< rm ... ./libmqcore32.so > ? n
< rm ... ./libq3di32.so > ? n
< rm ... ./libq3di32.a > ? n

use of scp

My memory is easy to forget, usually I am using tftp and nfs to share files, but I can not do it through ssh. When one door is close, there is another door open, I can use 'scp' from my Linux PC to transfer files.

clone jffs2

mount -t jffs2 /dev/mtdblock4 /mnt/nand
mount /dev/mmcblk0p2 /mnt/mmc2

I use mmc card as the media to save the rootfs at nand flash. It is not as easy as type: "tar czvf /mnt/mmc2/target.tar.gz /mnt/nand/". It won't work within busybox from the ARM target, could be the problem of tar.

How ever here is the magic:

tar cf - -C /mnt/nand . | tar xvf - -C /mnt/mmc2/target

Then pull the SD card and connect to the Linux PC, copy the file system with simply "cp -r /tftpboot /mnt/mmc2/target".

tftp on FC5

1. edit tftp file in "/etc/xinetd.d"

service tftp
{
disable = no
socket_type = dgram
protocol = yes
user = root
server = /usr/sbin/in.tftpd
server_args = -s /tftpboot
# disable = yes
per_source = 11
cps = 100 2
flags = IPv4
}

"/tftpboot" is my directory to be used by tftp. comment out "disable = yes" to enable tftp.

2. restart xinetd service.

$ sudo /sbin/service xinetd restart

compile mplayer with ALSA for ARM

1. download mplayer source code. I am using (MPlay-1.0rc2.tar.bz2)
2. extract it.
3. write a script mybuild.sh for configuring

export CROSS_CC=/opt/CodeSourcery/arm-2007q3-51
export PATH=$CROSS_CC/bin:$PATH
export TGT="your target file system"
./configure --enable-cross-compile -cc=arm-none-linux-gnueabi-gcc \
--host-cc=gcc --target=arm-linux --prefix=$TGT \
--disable-network --disable-x11 --disable-gui \
--with-extralibdir=$TGT/lib \
--with-extraincdir=$TGT/include

Here $TGT contains alsa include files and library "libasound.so.2".

4. type "make"